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  2. Petzval lens - Wikipedia

    en.wikipedia.org/wiki/Petzval_lens

    The Petzval objective, or Petzval lens, is the first photographic portrait objective lens (with a 160 mm focal length) in the history of photography. [1] It was developed by the Slovak mathematics professor Joseph Petzval in 1840 in Vienna , [ 2 ] with technical advice provided by Peter Wilhelm Friedrich von Voigtländer [ de ] .

  3. List of telescope parts and construction - Wikipedia

    en.wikipedia.org/wiki/List_of_telescope_parts...

    Objective: The first lens or curved mirror that collects and focuses the incoming light. Primary lens: The objective of a refracting telescope. Primary mirror: The objective of a reflecting telescope. Corrector plate: A full aperture negative lens placed before a primary mirror designed to correct the optical aberrations of the mirror.

  4. History of photographic lens design - Wikipedia

    en.wikipedia.org/wiki/History_of_photographic...

    However, for the record: the first autofocus lens for a still camera was the Konishiroku Konica Hexanon 38mm f/2.8 [171] built into the Konica C35 AF (1977, Japan) 35mm point-and-shoot; the first autofocus lens for an SLR camera was the unnamed 116mm f/8 [172] built into the Polaroid SX-70 Sonar (1978, USA) instant film SLR; the first ...

  5. Petzval field curvature - Wikipedia

    en.wikipedia.org/wiki/Petzval_field_curvature

    Lenses of short focal lengths (ultra wide, wide and normal) below 50 mm typically suffer more from field curvature. Telephoto lenses typically have very little or no visible field curvature. [ 2 ] The Petzval lens is one design which has significant field curvature; images taken with the lens are very sharp in the centre, but at greater angles ...

  6. Catadioptric system - Wikipedia

    en.wikipedia.org/wiki/Catadioptric_system

    This means the lens's F-number value is fixed to the overall designed focal ratio of the optical system (the diameter of the primary mirror divided into the focal length). The inability to stop down the lens results in the catadioptric lens having a short depth of field.

  7. Radius of curvature (optics) - Wikipedia

    en.wikipedia.org/wiki/Radius_of_curvature_(optics)

    A spherical lens or mirror surface has a center of curvature located either along or decentered from the system local optical axis. The vertex of the lens surface is located on the local optical axis. The distance from the vertex to the center of curvature is the radius of curvature of the surface.

  8. Is Alabama whining too much about missing the playoff? Yes ...

    www.aol.com/sports/alabama-whining-too-much...

    Disappointed with the outcome and felt we were one of the 12 best teams in the country. We had an extremely challenging schedule and recognize there were two games in particular that we did not ...

  9. Folded optics - Wikipedia

    en.wikipedia.org/wiki/Folded_optics

    Folded optics is an optical system in which the beam is bent in a way to make the optical path much longer than the size of the system. This allows the resulting focal length of the objective to be greater than the physical length of the optical device.